A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines.
A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine. In such engine architectures, a shaft driven by one of the turbine sections provides an input to the epicyclical gear assembly that drives the fan section at a reduced speed such that both the turbine section and the fan section can rotate at closer to optimal speeds.
The gear assembly is attached to a static structure through a flexible support. The flexible support orientates the gear assembly within the engine and also accommodates generated torque during operation. The support function includes a desired fit with static structure and is balanced against the torque transfer function. The configuration of the flexible support is therefore balanced against the desire to reduce cost and weight along with the separate functions. Accordingly, engine manufacturers continue to seek improvements in the support structure that balance the functional requirements against cost and weight.